The present invention relates to a novel organopolysiloxane and method for the preparation of same. More specifically, the present invention relates to an organopolysiloxane which bears at least two amino groups, carboxyl groups, hydroxyl groups, or epoxy-functional organic groups at one and only one of its molecular chain terminals, and to a method for the preparation of same.
Organofunctional group-containing ("organofunctionalized") organopolysiloxanes are employed in a wide range of fields as a fiber-treatment agent and as a modifying agent for organic resins. This type of organopolysiloxane is prepared by an addition reaction between SiH-containing organopolysiloxane and an organofunctionalized, aliphatically unsaturated hydrocarbon compound in the presence of a hydrosilylation-reaction catalyst. The number of organofunctional groups in the organopolysiloxane afforded thereby and its chemical structure are dictated by the SiH-containing organopolysiloxane employed as starting material.
In recent years, it has become necessary in the field of fine chemistry to control the number of organofunctional groups in organopolysiloxanes and the chemical structure of organopolysiloxanes. A particularly precise control of these parameters is required when the organopolysiloxane is to be employed as a modifier for organic resins.
However, the number of silicon-bonded hydrogens and the chemical structure in the SiH-containing organopolysiloxane precursor are both variable when this material is produced by an ionic equilibrium polymerization reaction. As a result, organopolysiloxanes prepared from such a starting material also have a variable number of organofunctional groups and a variable chemical structure. When such an organopolysiloxane is employed as a modifier for an organic resin, the effects deriving from modification in the organic resin afforded thereby are unsatisfactory.
On the other hand, the preparation of variously organofunctionalized organopolysiloxanes by a nonequilibrium polymerization reaction has been introduced. For example, in order to prepare an organopolysiloxane carrying organofunctionality at a single molecular chain terminal, a ring-opening polymerization is first run on hexaorganocyclotrisiloxane using alkyllithium or lithium silanolate as initiator. Stopping this reaction with dimethylchlorosilane affords an organopolysiloxane carrying silicon-bonded hydrogen at only one molecular chain terminal, which is subsequently addition-reacted with an organofunctionalized aliphatically unsaturated hydrocarbon compound in the presence of a hydrosilylation-reaction catalyst to afford the target material.
However, a drawback to this technique is that it affords only an organopolysiloxane carrying a single organofunctional group at the one molecular chain terminal.
With regard to the organopolysiloxane bearing at least 2 organofunctional groups at one and only one molecular chain terminal, Japanese Patent Application Laid Open [Kokai or Unexamined] Number 62-195389 [195,389/87] discloses an organopolysiloxane bearing the dicarbinol group at a single molecular chain terminal.
A problem with the organopolysiloxane disclosed in Japanese Patent Application Laid Open Number 62-195389 is that the organofunctional group is limited to the carbinol group.